I agree, you certainly need to get them laying before the older birds are molting. You can get stuck waiting until spring before they get going. That is expensive.
Winter laying is largely genetic, and partly management. Other than artificial lights, you can make sure the house gets plenty of sun in the winter. It does make a difference. A house sighted in winter shade gets less light than one with a clear southern exposure.
Identifying warmer parts of the yard helps moderate winter temperature's effects. In the south, the same location is a concern in the summer. Nothing comes without a cost.
Nutrition plays a part. Winter layers often do not have the access to the greens they might in longer day seasons.
A bird "feels" better when they have access to sunshine and fresh greens. Maximizing those two in the winter does help. A little cod liver oil does not hurt.
Some birds are better low light layers than others. For some reason my Catalanas are good winter layers. I still do not have a good feel for them. I had some odd winter molting and I hatched some too early, and they went into molt. I can give a more accurate picture in a couple years. I have seen enough to know that they are better winter layers than many I have had. Others have had this experience, so I am not alone.
Bee was right when she connected it to how good of layers they are anyways. A drop off in laying for some is as good as others are. That is a factor.
Mostly it goes back to the genetics of the line. It is not easy to improve upon either. The best you can do is identify the better winter layers (which often is the better layers overall), and test the males. That would be quite the process for a single trait. Alternately, you can avoid lights and hatch from late winter eggs. Over time, it seams that you would be inadvertently selecting for them.
That they molt out late and finish molting sooner can mean a few more out of season eggs, and identifying who comes into laying full steam early can mean teasing out a few more eggs. When it comes to winter laying without lights, small victories are big. You will not get full production, so teasing out an extra dozen from a single bird is an accomplishment.